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Trevor A. Jackson - One of the best experts on this subject based on the ideXlab platform.
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Pathology of Yersinia entomophaga MH96 towards Costelytra Zealandica (Coleoptera; Scarabaeidae) larvae.
Journal of invertebrate pathology, 2013Co-Authors: Mark R. H. Hurst, Chikako Van Koten, Trevor A. JacksonAbstract:Abstract The bacterium Yersinia entomophaga was isolated from larvae of the New Zealand grass grub, Costelytra Zealandica (Coleoptera: Scarabaeidae), found in soil. Following ingestion of a lethal dose of bacteria, larvae of C. Zealandica reduced feeding activity and movement. After approximately 4 h infected larvae convulsed and regurgitated dark digestive fluid and expelled frass pellets leaving the midgut empty and the larva amber in appearance. In the initial stages of infection, ingested bacteria were mostly contained within the peritrophic membrane and expelled with the gut fluid or transferred into the hind gut. While few Y. entomophaga were associated with the midgut epithelial cells, by 24 h cells were swelling and bursting with vesicles being expelled into the midgut lumen. By 48 h, bacteria had entered the haemocoel and the midgut cells had further deteriorated. After 72 h, the cellular remnants were totally detached from the basal membrane the infected insects were filled with bacteria and moribund or dead with septicaemia. Mortality was directly proportional to dose and time after infection. By applying a range of doses, the LD50 was determined as 2.9 × 104 Y. entomophaga per C. Zealandica larva, with an LT50 of 2.94 days for doses of >1 × 105 per larva. Ingestion of low doses of bacteria did not inhibit feeding activity but led more slowly to death. By time of death, Y. entomophaga had multiplied, approximately 500 fold, in the cadavers of the infected larvae.
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Serratia entomophila inoculation causes a defect in exocytosis in Costelytra Zealandica larvae.
Insect molecular biology, 2008Co-Authors: H.s. Gatehouse, Trevor A. Jackson, Sean D. G. Marshall, Robert M. Simpson, L.n. Gatehouse, John T. ChristellerAbstract:Rapid elimination of midgut luminal proteinase activity and gut clearance are the two major symptoms of amber disease in Costelytra Zealandica larvae because of the three-subunit protein toxin complex produced in Serratia entomophila and Serratia proteamaculans. Quantitative PCR analysis of mRNA from the major serine proteinase gene families showed that loss of proteinase activity did not result from transcriptional downregulation. Unexpectedly, protein levels and rates of protein synthesis increased, rather than decreased, in the midgut of diseased insects. Proteomic analysis of midgut tissues showed marked differences between healthy and diseased midguts. Large increases in soluble forms of both actin and tubulin were identified from 2D-gels, together with concurrent decreases in the levels of polymeric actin-associated proteins: actin depolymerizing factor and cyclophilin. These results suggest that the Serratia toxin acts to cause degradation of the cytoskeletal network and prevent secretion of midgut gut digestive proteinases as both the actin cytoskeleton and microtubules are involved in exocytosis. Proteinases synthesized in the diseased midgut must be rapidly degraded because they do not accumulate in an inactive form.
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Serine proteases identified from a Costelytra Zealandica (White) (Coleoptera: Scarabaeidae) midgut EST library and their expression through insect development.
Insect molecular biology, 2008Co-Authors: Sean D. G. Marshall, Mark R. H. Hurst, J. T. Christeller, H.s. Gatehouse, Laurence N. Gatehouse, S. A. Becher, Drion G. Boucias, Trevor A. JacksonAbstract:Costelytra Zealandica larvae are pests of New Zealand pastures causing damage by feeding on the roots of grasses and clovers. The major larval protein digestive enzymes are serine proteases (SPs), which are targets for disruption in pest control. An expressed sequence tag (EST) library from healthy, third instar larval midgut tissue was constructed and analysed to determine the composition and regulation of proteases in the C. Zealandica larval midgut. Gene mining identified three trypsin-like and 11 chymotrypsin-like SPs spread among four major subgroups. Representative SPs were examined by quantitative PCR and enzyme activity assayed across developmental stages. The serine protease genes examined were expressed throughout feeding stages and downregulated in nonfeeding stages. The study will improve targeting of protease inhibitors and bacterial disruptors of SP synthesis.
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Induced expression of the Serratia entomophila Sep proteins shows activity towards the larvae of the New Zealand grass grub Costelytra Zealandica.
FEMS microbiology letters, 2007Co-Authors: Mark R. H. Hurst, Binglin Tan, Sandra M. Jones, Trevor A. JacksonAbstract:Serratia entomophila and Serratia proteamaculans cause amber disease of the grass grub Costelytra Zealandica (Coleoptera: Scarabaeidae). Three genes required for virulence, sepABC, are located on a large plasmid, pADAP. The translated products of the sep genes are members of the toxin complex (Tc) family of insecticidal toxins that reside in the genomes of some Enterobacteriaceae. Each of the sep genes was placed either singly or as various combinations under the control of an inducible arabinose promoter, allowing their inductive expression. Western Immunoblot confirmed that each of the Sep proteins migrated at their predicted size on sodium dodecyl sulphate-polyacrylamide gel electrophoresis gel. Bioassays of sonicated filtrates derived from the various arabinose-induced para-SEP constructs showed that only when sepA, sepB and sepC were coexpressed were amber disease symptoms observed in grass grub larvae. Fourteen days after ingestion of the Sep protein filtrate, approximately 64% of the larvae reverted from a diseased to a healthy phenotype. Redosing the revertents with a fresh Sep protein filtrate reinitiated the amber pathotype, indicating that the Sep proteins are needed to be continuously present to exert an effect.
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Virulence of Serratia Strains against Costelytra Zealandica
Applied and environmental microbiology, 2006Co-Authors: Binglin Tan, Trevor A. Jackson, Mark R. H. HurstAbstract:Strains of Serratia spp. showed a high level of virulence when injected into the hemocoel of larvae Costelytra Zealandica, with Serratia entomophila, S. plymuthica, and S. marcescens showing significantly higher virulence than S. proteamaculans. Toxicity was independent of the amber disease-causing plasmid pADAP, suggesting a generalized Serratia toxin.
Travis R. Glare - One of the best experts on this subject based on the ideXlab platform.
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An improved method to produce adults of Costelytra Zealandica White (Coleoptera: Melolonthinae) from field-collected larvae
2017Co-Authors: M González-chang, Travis R. Glare, M-c Lefort, E Postic, S D WrattenAbstract:Rearing techniques provide a unique opportunity to study aspects of insect ecology, behaviour and physiology. Both the larval and adult stages in Melolonthinae scarabs have important impacts on crop and pasture yields worldwide. Rearing techniques for this group of phytophagous beetles usually results in a low survival rate from larva to adult, varying from 10% to 50%. Here, the current rearing method used for the New Zealand grass grub (Costelytra Zealandica) was improved by increasing the pupation weight threshold, as well as by changing the container type used to rear the larvae. This improved method produced an 83% increase in the survival rate from larva to adult, and the technique developed here may help increase the laboratory survival rate of other Melolonthinae species worldwide.
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Preference of a native beetle for “exoticism,” characteristics that contribute to invasive success of Costelytra Zealandica (Scarabaeidae: Melolonthinae)
PeerJ, 2015Co-Authors: Marie-caroline Lefort, Travis R. Glare, Stéphane Boyer, Jessica Vereijssen, Rowan Sprague, Susan P WornerAbstract:Widespread replacement of native ecosystems by productive land sometimes results in the outbreak of a native species. In New Zealand, the introduction of exotic pastoral plants has resulted in diet alteration of the native coleopteran species, Costelytra Zealandica (White) (Scarabaeidae) such that this insect has reached the status of pest. In contrast, C. brunneum (Broun), a congeneric species, has not developed such a relationship with these 'novel' host plants. This study investigated the feeding preferences and fitness performance of these two closely related scarab beetles to increase fundamental knowledge about the mechanisms responsible for the development of invasive characteristics in native insects. To this end, the feeding preference of third instar larvae of both Costelytra species was investigated using an olfactometer device, and the survival and larval growth of the invasive species C. Zealandica were compared on native and exotic host plants. Costelytra Zealandica, when sampled from exotic pastures, was unable to fully utilise its ancestral native host and showed higher feeding preference and performance on exotic plants. In contrast, C. Zealandica sampled from native grasslands did not perform significantly better on either host and showed similar feeding preferences to C. brunneum, which exhibited no feeding preference. This study suggests the possibility of strong intraspecific variation in the ability of C. Zealandica to exploit native or exotic plants, supporting the hypothesis that such ability underpins the existence of distinct host-races in this species.
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preference of a native beetle for exoticism characteristics that contribute to invasive success of Costelytra Zealandica scarabaeidae melolonthinae
PeerJ, 2015Co-Authors: Marie-caroline Lefort, Travis R. Glare, Stéphane Boyer, Jessica Vereijssen, Rowan Sprague, Susan P WornerAbstract:Widespread replacement of native ecosystems by productive land sometimes results in the outbreak of a native species. In New Zealand, the introduction of exotic pastoral plants has resulted in diet alteration of the native coleopteran species, Costelytra Zealandica (White) (Scarabaeidae) such that this insect has reached the status of pest. In contrast, C. brunneum (Broun), a congeneric species, has not developed such a relationship with these 'novel' host plants. This study investigated the feeding preferences and fitness performance of these two closely related scarab beetles to increase fundamental knowledge about the mechanisms responsible for the development of invasive characteristics in native insects. To this end, the feeding preference of third instar larvae of both Costelytra species was investigated using an olfactometer device, and the survival and larval growth of the invasive species C. Zealandica were compared on native and exotic host plants. Costelytra Zealandica, when sampled from exotic pastures, was unable to fully utilise its ancestral native host and showed higher feeding preference and performance on exotic plants. In contrast, C. Zealandica sampled from native grasslands did not perform significantly better on either host and showed similar feeding preferences to C. brunneum, which exhibited no feeding preference. This study suggests the possibility of strong intraspecific variation in the ability of C. Zealandica to exploit native or exotic plants, supporting the hypothesis that such ability underpins the existence of distinct host-races in this species.
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A native beetle fond of exotic plants. Characteristics that contribute to invasive success in Costelytra Zealandica (Scarabaeidae: Melolonthinae)
2015Co-Authors: Marie-caroline Lefort, Travis R. Glare, Stéphane Boyer, Jessica Vereijssen, Susan P WornerAbstract:Widespread replacement of native ecosystems by productive land sometimes results in the outbreak of a native species. In New Zealand, the introduction of exotic pastoral plants has resulted in the diet alteration of the native coleopteran species, Costelytra Zealandica (White) (Scarabaeidae) such that this insect has reached the status of pest. In contrast, C. brunneum (Broun), a close congeneric species, has not developed such a relationship with these ‘new’ host plants. This study investigated the feeding preferences and fitness performance of these two closely related scarab beetles to increase fundamental knowledge about the mechanisms responsible for the development of invasive characteristics in native insects. To this end the feeding preferences of larvae of both Costelytra species were investigated under controlled conditions and the survival and larval growth of the invasive species C. Zealandica were compared on native and exotic host plants. Costelytra Zealandica, when sampled from exotic pastures, was unable to fully utilise its ancestral native host and showed better performance on exotic plants. In contrast, C. Zealandica sampled from native grasslands did not perform significantly better on either host and showed similar feeding preferences to C. brunneum. This study suggests the possibility of strong intra-specific variation, in the ability of C. Zealandica to exploit native or exotic plants, supporting the hypothesis that such ability underpins the existence of distinct host-races in this species.
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Yersinia entomophaga sp. nov., isolated from the New Zealand grass grub Costelytra Zealandica
International Journal of Systematic and Evolutionary Microbiology, 2011Co-Authors: Mark R. H. Hurst, S. Anette Becher, Sandra Young, T.l. Nelson, Travis R. GlareAbstract:A Gram-negative, rod-shaped, non-spore-forming bacterium (MH96T) was isolated from diseased larvae of the New Zealand grass grub, Costelytra Zealandica (Coleoptera: Scarabaeidae). On the basis of 16S rRNA gene sequence similarity, strain MH96T is a member of the genus Yersinia, which is a member of the class Gammaproteobacteria. The most similar 16S rRNA gene sequence to that of MH96T is that of the type strain of Yersinia mollaretii (98.5 % similarity) followed by those of the type strains of Yersinia aldovae, Y. frederiksenii and Y. rohdei (all 98.4 % similarity). Multilocus sequence typing of five housekeeping genes (dnaJ, glnA, gyrB, groEL and recA) identified Yersinia ruckeri (81–92 % similarity) as the closest relative. The results of DNA–DNA hybridization and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain MH96T from the four most closely related Yersinia species with validly published names, including a Y. ruckeri isolate. Strain MH96T therefore represents a novel species, for which the name Yersinia entomophaga sp. nov. is proposed, with the type strain MH96T ( = DSM 22339T = ATCC BAA-1678T).
Mark R. H. Hurst - One of the best experts on this subject based on the ideXlab platform.
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Pathology of Yersinia entomophaga MH96 towards Costelytra Zealandica (Coleoptera; Scarabaeidae) larvae.
Journal of invertebrate pathology, 2013Co-Authors: Mark R. H. Hurst, Chikako Van Koten, Trevor A. JacksonAbstract:Abstract The bacterium Yersinia entomophaga was isolated from larvae of the New Zealand grass grub, Costelytra Zealandica (Coleoptera: Scarabaeidae), found in soil. Following ingestion of a lethal dose of bacteria, larvae of C. Zealandica reduced feeding activity and movement. After approximately 4 h infected larvae convulsed and regurgitated dark digestive fluid and expelled frass pellets leaving the midgut empty and the larva amber in appearance. In the initial stages of infection, ingested bacteria were mostly contained within the peritrophic membrane and expelled with the gut fluid or transferred into the hind gut. While few Y. entomophaga were associated with the midgut epithelial cells, by 24 h cells were swelling and bursting with vesicles being expelled into the midgut lumen. By 48 h, bacteria had entered the haemocoel and the midgut cells had further deteriorated. After 72 h, the cellular remnants were totally detached from the basal membrane the infected insects were filled with bacteria and moribund or dead with septicaemia. Mortality was directly proportional to dose and time after infection. By applying a range of doses, the LD50 was determined as 2.9 × 104 Y. entomophaga per C. Zealandica larva, with an LT50 of 2.94 days for doses of >1 × 105 per larva. Ingestion of low doses of bacteria did not inhibit feeding activity but led more slowly to death. By time of death, Y. entomophaga had multiplied, approximately 500 fold, in the cadavers of the infected larvae.
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Yersinia entomophaga sp. nov., isolated from the New Zealand grass grub Costelytra Zealandica
International Journal of Systematic and Evolutionary Microbiology, 2011Co-Authors: Mark R. H. Hurst, S. Anette Becher, Sandra Young, T.l. Nelson, Travis R. GlareAbstract:A Gram-negative, rod-shaped, non-spore-forming bacterium (MH96T) was isolated from diseased larvae of the New Zealand grass grub, Costelytra Zealandica (Coleoptera: Scarabaeidae). On the basis of 16S rRNA gene sequence similarity, strain MH96T is a member of the genus Yersinia, which is a member of the class Gammaproteobacteria. The most similar 16S rRNA gene sequence to that of MH96T is that of the type strain of Yersinia mollaretii (98.5 % similarity) followed by those of the type strains of Yersinia aldovae, Y. frederiksenii and Y. rohdei (all 98.4 % similarity). Multilocus sequence typing of five housekeeping genes (dnaJ, glnA, gyrB, groEL and recA) identified Yersinia ruckeri (81–92 % similarity) as the closest relative. The results of DNA–DNA hybridization and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain MH96T from the four most closely related Yersinia species with validly published names, including a Y. ruckeri isolate. Strain MH96T therefore represents a novel species, for which the name Yersinia entomophaga sp. nov. is proposed, with the type strain MH96T ( = DSM 22339T = ATCC BAA-1678T).
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Serine proteases identified from a Costelytra Zealandica (White) (Coleoptera: Scarabaeidae) midgut EST library and their expression through insect development.
Insect molecular biology, 2008Co-Authors: Sean D. G. Marshall, Mark R. H. Hurst, J. T. Christeller, H.s. Gatehouse, Laurence N. Gatehouse, S. A. Becher, Drion G. Boucias, Trevor A. JacksonAbstract:Costelytra Zealandica larvae are pests of New Zealand pastures causing damage by feeding on the roots of grasses and clovers. The major larval protein digestive enzymes are serine proteases (SPs), which are targets for disruption in pest control. An expressed sequence tag (EST) library from healthy, third instar larval midgut tissue was constructed and analysed to determine the composition and regulation of proteases in the C. Zealandica larval midgut. Gene mining identified three trypsin-like and 11 chymotrypsin-like SPs spread among four major subgroups. Representative SPs were examined by quantitative PCR and enzyme activity assayed across developmental stages. The serine protease genes examined were expressed throughout feeding stages and downregulated in nonfeeding stages. The study will improve targeting of protease inhibitors and bacterial disruptors of SP synthesis.
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Induced expression of the Serratia entomophila Sep proteins shows activity towards the larvae of the New Zealand grass grub Costelytra Zealandica.
FEMS microbiology letters, 2007Co-Authors: Mark R. H. Hurst, Binglin Tan, Sandra M. Jones, Trevor A. JacksonAbstract:Serratia entomophila and Serratia proteamaculans cause amber disease of the grass grub Costelytra Zealandica (Coleoptera: Scarabaeidae). Three genes required for virulence, sepABC, are located on a large plasmid, pADAP. The translated products of the sep genes are members of the toxin complex (Tc) family of insecticidal toxins that reside in the genomes of some Enterobacteriaceae. Each of the sep genes was placed either singly or as various combinations under the control of an inducible arabinose promoter, allowing their inductive expression. Western Immunoblot confirmed that each of the Sep proteins migrated at their predicted size on sodium dodecyl sulphate-polyacrylamide gel electrophoresis gel. Bioassays of sonicated filtrates derived from the various arabinose-induced para-SEP constructs showed that only when sepA, sepB and sepC were coexpressed were amber disease symptoms observed in grass grub larvae. Fourteen days after ingestion of the Sep protein filtrate, approximately 64% of the larvae reverted from a diseased to a healthy phenotype. Redosing the revertents with a fresh Sep protein filtrate reinitiated the amber pathotype, indicating that the Sep proteins are needed to be continuously present to exert an effect.
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Virulence of Serratia Strains against Costelytra Zealandica
Applied and environmental microbiology, 2006Co-Authors: Binglin Tan, Trevor A. Jackson, Mark R. H. HurstAbstract:Strains of Serratia spp. showed a high level of virulence when injected into the hemocoel of larvae Costelytra Zealandica, with Serratia entomophila, S. plymuthica, and S. marcescens showing significantly higher virulence than S. proteamaculans. Toxicity was independent of the amber disease-causing plasmid pADAP, suggesting a generalized Serratia toxin.
Stéphane Boyer - One of the best experts on this subject based on the ideXlab platform.
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preference of a native beetle for exoticism characteristics that contribute to invasive success of Costelytra Zealandica scarabaeidae melolonthinae
PeerJ, 2015Co-Authors: Marie-caroline Lefort, Travis R. Glare, Stéphane Boyer, Jessica Vereijssen, Rowan Sprague, Susan P WornerAbstract:Widespread replacement of native ecosystems by productive land sometimes results in the outbreak of a native species. In New Zealand, the introduction of exotic pastoral plants has resulted in diet alteration of the native coleopteran species, Costelytra Zealandica (White) (Scarabaeidae) such that this insect has reached the status of pest. In contrast, C. brunneum (Broun), a congeneric species, has not developed such a relationship with these 'novel' host plants. This study investigated the feeding preferences and fitness performance of these two closely related scarab beetles to increase fundamental knowledge about the mechanisms responsible for the development of invasive characteristics in native insects. To this end, the feeding preference of third instar larvae of both Costelytra species was investigated using an olfactometer device, and the survival and larval growth of the invasive species C. Zealandica were compared on native and exotic host plants. Costelytra Zealandica, when sampled from exotic pastures, was unable to fully utilise its ancestral native host and showed higher feeding preference and performance on exotic plants. In contrast, C. Zealandica sampled from native grasslands did not perform significantly better on either host and showed similar feeding preferences to C. brunneum, which exhibited no feeding preference. This study suggests the possibility of strong intraspecific variation in the ability of C. Zealandica to exploit native or exotic plants, supporting the hypothesis that such ability underpins the existence of distinct host-races in this species.
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Preference of a native beetle for “exoticism,” characteristics that contribute to invasive success of Costelytra Zealandica (Scarabaeidae: Melolonthinae)
PeerJ, 2015Co-Authors: Marie-caroline Lefort, Travis R. Glare, Stéphane Boyer, Jessica Vereijssen, Rowan Sprague, Susan P WornerAbstract:Widespread replacement of native ecosystems by productive land sometimes results in the outbreak of a native species. In New Zealand, the introduction of exotic pastoral plants has resulted in diet alteration of the native coleopteran species, Costelytra Zealandica (White) (Scarabaeidae) such that this insect has reached the status of pest. In contrast, C. brunneum (Broun), a congeneric species, has not developed such a relationship with these 'novel' host plants. This study investigated the feeding preferences and fitness performance of these two closely related scarab beetles to increase fundamental knowledge about the mechanisms responsible for the development of invasive characteristics in native insects. To this end, the feeding preference of third instar larvae of both Costelytra species was investigated using an olfactometer device, and the survival and larval growth of the invasive species C. Zealandica were compared on native and exotic host plants. Costelytra Zealandica, when sampled from exotic pastures, was unable to fully utilise its ancestral native host and showed higher feeding preference and performance on exotic plants. In contrast, C. Zealandica sampled from native grasslands did not perform significantly better on either host and showed similar feeding preferences to C. brunneum, which exhibited no feeding preference. This study suggests the possibility of strong intraspecific variation in the ability of C. Zealandica to exploit native or exotic plants, supporting the hypothesis that such ability underpins the existence of distinct host-races in this species.
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A native beetle fond of exotic plants. Characteristics that contribute to invasive success in Costelytra Zealandica (Scarabaeidae: Melolonthinae)
2015Co-Authors: Marie-caroline Lefort, Travis R. Glare, Stéphane Boyer, Jessica Vereijssen, Susan P WornerAbstract:Widespread replacement of native ecosystems by productive land sometimes results in the outbreak of a native species. In New Zealand, the introduction of exotic pastoral plants has resulted in the diet alteration of the native coleopteran species, Costelytra Zealandica (White) (Scarabaeidae) such that this insect has reached the status of pest. In contrast, C. brunneum (Broun), a close congeneric species, has not developed such a relationship with these ‘new’ host plants. This study investigated the feeding preferences and fitness performance of these two closely related scarab beetles to increase fundamental knowledge about the mechanisms responsible for the development of invasive characteristics in native insects. To this end the feeding preferences of larvae of both Costelytra species were investigated under controlled conditions and the survival and larval growth of the invasive species C. Zealandica were compared on native and exotic host plants. Costelytra Zealandica, when sampled from exotic pastures, was unable to fully utilise its ancestral native host and showed better performance on exotic plants. In contrast, C. Zealandica sampled from native grasslands did not perform significantly better on either host and showed similar feeding preferences to C. brunneum. This study suggests the possibility of strong intra-specific variation, in the ability of C. Zealandica to exploit native or exotic plants, supporting the hypothesis that such ability underpins the existence of distinct host-races in this species.
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Combining molecular and morphological approaches to differentiate the pest Costelytra Zealandica (White) (Coleoptera: Scarabeidae: Melolonthinae) from the non-pest Costelytra brunneum (Broun) at the larval stage
New Zealand Entomologist, 2013Co-Authors: M-c Lefort, John W. M. Marris, Barbara I. P. Barratt, Stéphane BoyerAbstract:The frequently strong morphological similarities that exist between the larvae of congeneric scarab beetles are likely to lead to misidentification of field-collected specimens of sympatric species. This is the case for the New Zealand endemic pasture pest Costelytra Zealandica (White, 1846) (Scarabaeidae: Melolonthinae) and the closely related non-pest species C. brunneum (Broun, 1880), where a taxonomic key is only available for C. Zealandica and does not allow the distinction between the two species. Mistaken identification and sampling of such fundamentally different organisms during ecological and/or behavioural studies could lead to invalid interpretations and misinformed decisions in the establishment of pest control programs. Molecular-based species identification is nowadays recognised as an effective way to identify cryptic species using barcoding regions of the genome. In this paper, we coupled this genetic approach with traditional scarab taxonomy (i.e. morphology of the raster, mandibles, lab...
Sean D. G. Marshall - One of the best experts on this subject based on the ideXlab platform.
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Serratia entomophila inoculation causes a defect in exocytosis in Costelytra Zealandica larvae.
Insect molecular biology, 2008Co-Authors: H.s. Gatehouse, Trevor A. Jackson, Sean D. G. Marshall, Robert M. Simpson, L.n. Gatehouse, John T. ChristellerAbstract:Rapid elimination of midgut luminal proteinase activity and gut clearance are the two major symptoms of amber disease in Costelytra Zealandica larvae because of the three-subunit protein toxin complex produced in Serratia entomophila and Serratia proteamaculans. Quantitative PCR analysis of mRNA from the major serine proteinase gene families showed that loss of proteinase activity did not result from transcriptional downregulation. Unexpectedly, protein levels and rates of protein synthesis increased, rather than decreased, in the midgut of diseased insects. Proteomic analysis of midgut tissues showed marked differences between healthy and diseased midguts. Large increases in soluble forms of both actin and tubulin were identified from 2D-gels, together with concurrent decreases in the levels of polymeric actin-associated proteins: actin depolymerizing factor and cyclophilin. These results suggest that the Serratia toxin acts to cause degradation of the cytoskeletal network and prevent secretion of midgut gut digestive proteinases as both the actin cytoskeleton and microtubules are involved in exocytosis. Proteinases synthesized in the diseased midgut must be rapidly degraded because they do not accumulate in an inactive form.
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Serine proteases identified from a Costelytra Zealandica (White) (Coleoptera: Scarabaeidae) midgut EST library and their expression through insect development.
Insect molecular biology, 2008Co-Authors: Sean D. G. Marshall, Mark R. H. Hurst, J. T. Christeller, H.s. Gatehouse, Laurence N. Gatehouse, S. A. Becher, Drion G. Boucias, Trevor A. JacksonAbstract:Costelytra Zealandica larvae are pests of New Zealand pastures causing damage by feeding on the roots of grasses and clovers. The major larval protein digestive enzymes are serine proteases (SPs), which are targets for disruption in pest control. An expressed sequence tag (EST) library from healthy, third instar larval midgut tissue was constructed and analysed to determine the composition and regulation of proteases in the C. Zealandica larval midgut. Gene mining identified three trypsin-like and 11 chymotrypsin-like SPs spread among four major subgroups. Representative SPs were examined by quantitative PCR and enzyme activity assayed across developmental stages. The serine protease genes examined were expressed throughout feeding stages and downregulated in nonfeeding stages. The study will improve targeting of protease inhibitors and bacterial disruptors of SP synthesis.
